Aquarium Fish Database

Explore freshwater aquarium fish by care level, size, temperament, swimming zone, water parameters, and compatibility.

Intermediate – Advanced

Meghalaya Leopard Snakehead

Channa paradalis

Adult size
≤ 5.9" (≤ 15 cm)
Aquarium size
106 US gal (400 L) or larger / ≥ 47.2" (≥ 120 cm) minimum length
Temperament
Aggressive
Zone
Bottom to middle swimmer
Temp
68–82°F (20–28°C)
Intermediate

Melanzona Guppy

Poecilia parae

Adult size
≤ 2" (≤ 5 cm)
Aquarium size
14 US gal (54 L) or larger / ≥ 23.6" (≥ 60 cm) minimum length
Temperament
Peaceful
Zone
Middle to top swimmer
Temp
73–81°F (23–27°C)
Beginner – Intermediate

Melon Barb

Haludaria fasciata

Adult size
≤ 2.4" (≤ 6 cm)
Aquarium size
21 US gal (81 L) or larger / ≥ 47.2" (≥ 120 cm) minimum length
Temperament
Peaceful
Zone
Bottom to middle swimmer
Temp
72–79°F (22–26°C)
Beginner – Intermediate

Mendezi Dwarf Cichlid

Apistogramma mendezi

Adult size
≤ 2.8" (≤ 7 cm)
Aquarium size
24 US gal (90 L) or larger / ≥ 39.4" (≥ 100 cm) minimum length
Temperament
Peaceful
Zone
Bottom to middle swimmer
Temp
73–84°F (23–29°C)
Beginner

Merry Widow Livebearer

Phallichthys amates

Adult size
≤ 2.8" (≤ 7 cm)
Aquarium size
16 US gal (60 L) or larger / ≥ 15.7" (≥ 40 cm) minimum length
Temperament
Peaceful
Temp
73–79°F (23–26°C)
Beginner – Intermediate

Mexican Tetra

Astyanax mexicanus

Adult size
≤ 4.7" (≤ 12 cm)
Aquarium size
20 US gal (75 L) or larger / ≥ 35.4" (≥ 90 cm) minimum length
Temperament
Peaceful
Zone
Middle swimmer
Temp
68–77°F (20–25°C)
Beginner – Intermediate

Mimicry Otocinclus

Otocinclus mimulus

Adult size
≤ 1.8" (≤ 4.5 cm)
Aquarium size
30 US gal (112 L) or larger / ≥ 31.5" (≥ 80 cm) minimum length
Temperament
Peaceful
Zone
Bottom to middle swimmer
Temp
72–79°F (22–26°C)
Beginner – Intermediate

Mini Rosy Tetra

Hyphessobrycon dorsalis

Adult size
≤ 1.2" (≤ 3 cm)
Temperament
Peaceful
Zone
Middle to top swimmer
Temp
73–82°F (23–28°C)
Beginner – Intermediate

Miniature Pencilfish

Nannostomus anduzei

Adult size
≤ 0.8" (≤ 2 cm)
Aquarium size
11 US gal (41 L) or larger / ≥ 17.7" (≥ 45 cm) minimum length
Temperament
Peaceful
Zone
Middle to top swimmer
Temp
72–82°F (22–28°C)
Intermediate

Mirabilis Eartheater

Geophagus mirabilis

Adult size
≤ 7.9" (≤ 20 cm)
Aquarium size
79 US gal (300 L) or larger / ≥ 59.1" (≥ 150 cm) minimum length
Temperament
Peaceful
Zone
Middle swimmer
Temp
72–86°F (22–30°C)
Beginner – Intermediate

Molly

Poecilia latipinna

Adult size
≤ 4.7" (≤ 12 cm)
Aquarium size
53 US gal (200 L) or larger / ≥ 31.5" (≥ 80 cm) minimum length
Temperament
Peaceful
Temp
72–79°F (22–26°C)
Beginner – Intermediate

Monica’s Tetra

Moenkhausia monicae

Adult size
≤ 2" (≤ 5 cm)
Temperament
Peaceful
Zone
Middle to top swimmer
Temp
72–79°F (22–26°C)
Beginner – Intermediate

Monkey Goby

Neogobius fluviatilis

Adult size
≤ 7.9" (≤ 20 cm)
Aquarium size
20 US gal (76 L) or larger
Temperament
Peaceful
Zone
Bottom dweller
Temp
39–68°F (4–20°C)
Beginner – Intermediate

Montags Tetra

Hyphessobrycon montagi

Adult size
≤ 1.2" (≤ 3 cm)
Aquarium size
20 US gal (76 L) or larger
Temperament
Peaceful
Zone
Middle to top swimmer
Temp
72–81°F (22–27°C)
Beginner – Intermediate

Moonlight Gourami

Trichopodus microlepis

Adult size
≤ 5.9" (≤ 15 cm)
Aquarium size
40 US gal (150 L) or larger / ≥ 47.2" (≥ 120 cm) minimum length
Temperament
Peaceful
Zone
Middle to top swimmer
Temp
72–86°F (22–30°C)
Intermediate

Morse Knifefish

Gymnorhamphichthys hypostomus

Adult size
≤ 8.5" (≤ 21.5 cm)
Aquarium size
53 US gal (200 L) or larger
Temperament
Peaceful
Zone
Bottom to middle swimmer
Temp
77–82°F (25–28°C)
Intermediate – Advanced

Motoro Stingray

Potamotrygon motoro

Adult size
≤ 35.4" (≤ 90 cm)
Aquarium size
449 US gal (1700 L) or larger / ≥ 94.5" (≥ 240 cm) minimum length
Temperament
Peaceful
Zone
Bottom dweller
Temp
75–79°F (24–26°C)
Beginner – Intermediate

Mottled Ctenopoma

Ctenopoma weeksii

Adult size
≤ 4.7" (≤ 12 cm)
Aquarium size
26 US gal (100 L) or larger / ≥ 29.5" (≥ 75 cm) minimum length
Temperament
Peaceful
Zone
Bottom to middle swimmer
Temp
73–81°F (23–27°C)
Beginner – Intermediate

Mountain Redbelly Dace

Chrosomus oreas

Adult size
≤ 2.8" (≤ 7 cm)
Temperament
Peaceful
Zone
Middle to top swimmer
Temp
59–77°F (15–25°C)
Intermediate

Mousetail Knifefish

Gymnorhamphichthys rondoni

Adult size
≤ 5.9" (≤ 15 cm)
Aquarium size
53 US gal (200 L) or larger
Temperament
Peaceful
Zone
Bottom to middle swimmer
Temp
77–82°F (25–28°C)
Beginner

Moustached Danio

Danio dangila

Adult size
≤ 4.7" (≤ 12 cm)
Aquarium size
64 US gal (243 L) or larger / ≥ 47.2" (≥ 120 cm) minimum length
Temperament
Peaceful
Zone
Middle to top swimmer
Temp
61–75°F (16–24°C)
Beginner – Intermediate

Murray River Rainbowfish

Melanotaenia fluviatilis

Adult size
≤ 3.9" (≤ 10 cm)
Aquarium size
48 US gal (180 L) or larger / ≥ 35.4" (≥ 90 cm) minimum length
Temperament
Peaceful
Zone
Middle to top swimmer
Temp
68–77°F (20–25°C)
Beginner – Intermediate

Myer’s Hillstream Loach

Pseudogastromyzon myersi

Adult size
≤ 2.4" (≤ 6 cm)
Aquarium size
16 US gal (60 L) or larger / ≥ 31.5" (≥ 80 cm) minimum length
Temperament
Peaceful
Zone
Bottom dweller
Temp
68–75°F (20–24°C)
Beginner – Intermediate

Napo Corydoras

Gastrodermus napoensis

Adult size
≤ 2" (≤ 5 cm)
Aquarium size
16 US gal (60 L) or larger / ≥ 23.6" (≥ 60 cm) minimum length
Temperament
Peaceful
Zone
Bottom dweller
Temp
72–79°F (22–26°C)
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